Succinct representation of dynamic trees

We study the problem of maintaining a dynamic ordered tree succinctly under updates of the following form: insertion or deletion of a leaf, insertion of a node on an edge (edge subdivision) or deletion of a node with only one child (the child becomes a child of its former grandparent). We allow satellite data of a fixed size to be associated to the nodes of the tree.We support update operations in constant amortized time and support access to satellite data and basic navigation operations in worst-case constant time; the basic navigation operations include parent, first/last-child, previous/next-child. These operations are moving from a node to its parent, leftmost/rightmost child, and its previous and next child respectively.We demonstrate that to efficiently support more extended operations, such as determining the i-th child of a node, rank of a child among its siblings, or size of the subtree rooted at a node, one requires a restrictive pattern for update strategy, for which we propose the finger-update model. In this model, updates are performed at the location of a finger that is only allowed to crawl on the tree between a child and a parent or between consecutive siblings. Under this model, we describe how the named extended operations are performed in worst-case constant time.Previous work on dynamic succinct trees (Munro et al., 2001 [17]; Raman and Rao, 2003 [19]) is mainly restricted to binary trees and achieves poly-logarithmic (Munro et al., 2001 [17]) or “poly-log-log” (Raman and Rao, 2003 [19]) update time under a more restricted model, where updates are performed in traversals starting at the root and ending at the root and queries can be answered when the traversal is completed. A previous result on ordinal trees achieves only sublinear amortized update time and “poly-log-log” query time (Gupta et al., 2007 [11]). More recently, the update time has been improved to O(logn/loglogn) while queries can be performed in O(logn/loglogn) time (Sadakane and Navarro, 2010 [20]).     

A robust and flexible digital rights management system for home networks

A robust and flexible Digital Rights Management system for home networks is presented. In the proposed system, the central authority delegates its authorization right to the local manager in a home network by issuing a proxy certificate, and the local manager flexibly controls the access rights of home devices on digital contents with its proxy certificate. Furthermore, the proposed system provides a temporary accessing facility for external devices and achieves strong privacy for home devices. For the validation of delegated rights and the revocation of compromised local managers, a hybrid mechanism combining OCSP validation and periodic renewal of proxy certificates is also presented.     

Reconstructing an image from its edge representation

In this paper, we show that a new edge detection scheme developed from the notion of transition in nonlinear physics, associated with the precise computation of its quantitative parameters (most notably singularity exponents) provide enhanced performances in terms of reconstruction of the whole image from its edge representation; moreover it is naturally robust to noise. The study of biological vision in mammals state the fact that major information in an image is encoded in its edges, the idea further supported by neurophysics. The first conclusion that can be drawn from this stated fact is that of being able to reconstruct accurately an image from the compact representation of its edge pixels. The paper focuses on how the idea of edge completion can be assessed quantitatively from the framework of reconstructible systems when evaluated in a microcanonical formulation; and how it redefines the adequation of edge as candidates for compact representation. In the process of doing so, we also propose an algorithm for image reconstruction from its edge feature and show that this new algorithm outperforms the well-known ‘state-of-the-art’ techniques, in terms of compact representation, in majority of the cases.     

Who should own access rights? A game-theoretical approach to striking the optimal balance in the debate over Digital Rights Management

The development of access rights as, perhaps, a replacement for copyright in digital rights management (DRM) systems, draws our attention to the importance of ‚the balance problem’ between information industries and the individual user. The nature of just what this ‚balance’ is, is often mentioned in copyright writings and judgments, but is rarely discussed. In this paper I focus upon elucidating the idea of balance in intellectual property and propose that the balance concept is not only the most feasible way to examine whether past solutions to copyright problems are fair, but it also provides the ability to predict what will be the better solution for all affected parties. Based upon an envy-free contribution towards predicting the efficient balance, game theory is applied in a novel manner to the DRM problem to infer where and what might be the optimal balance in the debate over the nature of access right.     

基于RBR和CBR规划中的知识表示方法研究

知识是规划的前提和基础,通过归纳对已有知识的表示,就成为了规划的先行条件.基于规则和案例的规划是各种现代规划器常用的两种规划方式,通过对现有的规则和案例的各种知识表示方法的研究,描述了其各自的优缺点,并给出了如何选择合适的知识表示方法以处理特定规划问题的方法和思想,从而更快,更好的构建能够解决实际问题的规划系统.     

Dynamic modelling, simulation and control of a manipulator with flexible links and joints

The paper presents a dynamic modelling technique for a manipulator with multiple flexible links and flexible joints, based on a combined Euler–Lagrange formulation and assumed modes method. The resulting generalised model is validated through computer simulations by considering a simplified case study of a two-link flexible manipulator with joint elasticity. Controlling such a manipulator is more complex than controlling one with rigid joints because only a single actuation signal can be applied at each joint and this has to control the flexure of both the joint itself and the link attached to it. To resolve the control complexities associated with such an under-actuated flexible link/flexible joint manipulator, a singularly perturbed model has been formulated and used to design a reduced-order controller. This is shown to stabilise the link and joint vibrations effectively while maintaining good tracking performance.     

一种四维访问矩阵模型的建立

传统的主体一客体访问矩阵模型缺少对动态因素的描述,故应用在刻画系统中具体的资源访问活动时存在着许多不足,如无法实现“最小特权”原则和缺乏对访问授权时间特性的控制。引入可执行程序及时间两维,提出的四维访问控制模型很好地弥补了上述的不足。     

Symbolic representation of user-defined time granularities

In the recent literature on time representation, an effort has been made to characterize the notion of time granularity and the relationships between granularities. The main goals are having a common framework for their specification, and allowing the interoperability of systems adopting different time granularities. This paper considers the mathematical characterization of finite and periodic time granularities, and investigates the requirements for a user-friendly symbolic formalism that could be used for their specification. Instead of proposing yet another formalism, the paper analyzes the expressiveness of known symbolic formalisms for the representation of granularities, using the mathematical characterization as a reference model. Based on this analysis, a significant extension to the collection formalism defined in [15] is proposed, in order to capture a practically interesting class of periodic granularities. This revised version was published online in June 2006 with corrections to the Cover Date.     

立体化学在计算机中的识别和表征

利用奇偶值在计算机中对立体化学进行表征可以避免复杂的CIP规则。本文对立体化学在计算机中的表征方法进行了讨论,并具体描述了立体化学的奇偶表征方法。文中将立体中心进行了分类,对每一类立体中心的构型的计算进行了讨论。并将奇偶方法的应用范围扩展到了对阻转异构体构型的表征,以及对虚拟轴立体中心的表征。此表征方法在化合物登录系统中的应用得到了很好的结果。     

远程接入中的安全访问控制

以实际项目应用为例,利用VPN、防火墙、策略交换机等几种典型设备,对解决企业的远程办公接入问题进行深入探究。     

A survey of flexible manufacturing systems

In this report, the different flexible manufacturing systems used for machining and assembling in the following countries are reviewed: the United States, Japan, the Federal Republic of Germany, the German Democratic Republic, Italy, Great Britain, Sweden, Norway, France, Czechoslovakia and Hungary.Three categories of systems discussed are (1) flexible modules and units, (2) flexible transfer lines, and (3) “unaligned” flexible systems. Within each category are several sub-groups, divided up mainly according to the conveyor system and operating mode. This classification shows the effective French position in this field.     

Framework of a flexible computer communication network

With the increasing speed of computers and communication links, and the successful convergence of both fields, computers connected by high speed links now represent an enormously large distributed computing system. At the same time, communication between man and machine is also becoming more diverse and personalized. Networking issues such as evolution of user services, seamless communication between hosts, failure recovery and integration of new technologies arise daily. Problem-specific approaches and corresponding solutions are available at considerable cost. However, a common requirement is adaptability of the computer network to a variety of changes. In this paper, we propose Flexible Computer Communication Networks (FN) as a uniform solution to most of these networking problems. The framework of Flexible Networks can be considered as an intelligent shell enclosing existing networking architectures. An agent-oriented implementation of a flexible network is outlined. The conversion of existing networks to flexible networks is shown to be incremental, and therefore practicable.     

MTOL网络接入流程及接入失败分析

本文主要分析MTOL的接入流程,是从移动台发起呼叫请求到通话建立的过程,在这个过程中会有多种多样的原因导致接入失败,本文重点分析移动台是如何接入网络的,以及在无线侧导致接入失败的原因,并以2009年2月DT测试为样本,选取典型事件,对接入异常事件做一个简单TOPN分析并提出解决建议。     

Stability evaluation and system identification of flexible multibody systems

This paper is concerned with the linearized stability analysis and system identification of flexible multibody systems. Two closely related stability analysis approaches are summarized. Next, these approaches are extended to provide robust system identification procedures that combine least squares techniques and Kalman filters. The singular value decomposition, a numerically stable mathematical tool, is used to improve the robustness of the algorithm. The proposed algorithm identifies a minimum order plant based on input-output data, and is applicable to both experimental measurements or numerically computed responses. The proposed approaches are computationally inexpensive and consist of purely post processing steps that can be used with any multi-physics computational multibody tool or with experimental data. Commemorative Contribution.     

Context and its representation

Recent work in HCI has argued that an adequate account of computer use and the user's understandings should pay attention to the contexts in which interactions take place. The paper reaffirms this claim and distinguishes some variants of it, but simultaneously argues that the specification of what is to count as ‘context’ is more problematic than is often supposed. Some empirical data in the form of a transcribed videotape of one interaction is discussed to illustrate the argument. Finally some implications for HCI are briefly considered.     

Optimal control of a single-link flexible manipulator

This paper deals with an exact state space dynamic model for manipulators with flexible links. We use the Bernoulli-Euler beam equations to derive a frequency domain matrix transfer function. This transfer function is then used to compute the Laplace transform of the state vector as a function of the lateral position along a single link manipulator. The problem of optimal end point control of the beam is then addressed. A sixth-order state space model is derived for the manipulator and the controller is based on this model. Several control laws are studied for this model. Next, the manipulator is modeled as eighth order but the control law based on the sixth-order model is retained. We then estimate the six states from the output of the eighth-order model and feed these states back to the controller to derive the control torque used to drive the manipulator. A filter is introduced to compensate for spillover. The results are very satisfactory, and are illustrated by simulated case studies.     

A representation and the norm of Toeplitz operators

The Toeplitz operator has been used in system and control theory for quite a long time. Recently, it played a conspoicuous in H_∞-control theory. One of the important properties of the Toeplitz operator is that its norm is identical to the norm of the Laurent operator with the same symbol. The original proof of this property relies on some advanced tools in operator theory. In this paper, for Toeplitz operators with symbols consisting of an infinite-dimensional stable part and a finite-dimensional unstable part, an elementary and self-contained proof of this property is given. Our proof is based on a representation of the Toeplitz operator presented in this paper and the well known fact that an inner matrix defines an isometry. The representation presented in this paper gives insight into the structure of the Toeplitz operator. A further application of this representation is also presented.     

安全访问控制系统的设计和实现

访问控制是现代企业信息系统设计的核心,它控制用户行为,保护系统资源的安全。传统的访问控制模块的设计与应用系统紧密耦合,使其无法得到很好的复用。本文介绍了轻量级目录访问控制协议(LightweightDirectoryAccessProtocol,简称LDAP)和基于角色的访问控制基于角色的访问控制(Role-basedAccessControl,简称RBAC)模型,基于它们设计了一个高效、安全的访问控制系统。该系统在省邮政综合服务平台中的到应用,有效解决了原有系统设计中的一些弊端。